A portable terminal refers to a small electronic device to be carried easily by a user in order to perform a function such as game or mobile communication. A portable terminal can be a mobile communication terminal, a personal digital assistant (PDA) or a portable multimedia player (PMP).
A mobile communication terminal in general is a device designed to allow a mobile user to telecommunicate with a remotely-located receiver. However, technological developments have recently added extra functions, such as the camera function or multi media data playback function, to essential functions, such as the mobile communication function or Short Message Service (SMS), of a mobile communication terminal.
FIG. 1 shows a block diagram of a conventional mobile communication terminal having a camera function.
Referring to FIG. 1, a mobile communication terminal 100 having a camera function comprises a high frequency processing unit 110, an A/D conversion unit 115, a D/A conversion unit 120, a control unit 125, a power supply unit 130, a key input unit 135, a memory unit 140, a display unit 145, a camera unit 150, and an image processing unit 155.
The high frequency processing unit 110 processes a high frequency signal, which is transmitted or received through an antenna.
The A/D conversion unit 115 converts an analog electrical signal, received from the high frequency processing unit 110, to a digital output signal and sends to the control unit 125.
The D/A conversion unit 120 converts a digital electrical signal, received from the control unit 125, to an analog output signal and sends to the high frequency processing unit 110.
The control unit 125 controls the general operation of the mobile communication terminal 100. The control unit 125 can comprise, for example, a central processing unit (CPU) or micro-controller.
The power supply unit 130 supplies electric power required for operating the mobile communication terminal 100. The power supply unit 130 can be connected to, for example, an external power source or battery.
The key input unit 135 generates key data for setting various functions of the mobile communication terminal 100 or dialing and sends to the control unit 125.
The memory unit 140 stores an operating system, a variety of data, etc. of the mobile communication terminal 100. The memory unit 140 can consist of, for example, a flash memory, an EEPROM (Electrically Erasable Programmable Read Only Memory), etc.
The display unit 145 displays the operation status of the mobile communication terminal 100 and an external image photographed by the camera unit 150.
The camera unit 150 photographs an external image (a photographic subject), and the image processing unit 155 processes the photographed external image. The image processing unit can perform functions such as color interpolation, gamma correction, image quality correction, and JPEG decoding.
As described above, a mobile communication terminal 100 having a camera function is equipped with a plurality of processors (that is, a main controller and one or more sub-controllers for controlling an additional function controlled by the main controller). In other words, a mobile communication terminal 100 having a camera function comprises a control unit 125 for controlling the general function of the mobile communication terminal 100 and an image-processing unit 155 for controlling the camera function.
The sub-controller can take different forms depending on the kinds of additional functions, with which the portable terminal is equipped. For example, a sub-controller for controlling a camera function can process functions such as JPEG encoding or JPEG decoding; a sub-controller for controlling a movie file playback function can process functions such as video file (e.g., MPEG4, DIVX, or H.264) encoding or decoding; and a sub-controller for controlling a music file playback function can process functions such as audio file encoding or decoding. Of course, there can be a sub-controller that can process various aforementioned functions together.
However, since the main memory has a serial structure between the main controller and sub-controller in the conventional art, the processing power can experience weakening or bottleneck during the transmission of message, and development of programs has been increasingly complicated due to the interaction.